1. Field of the Invention
The present invention relates generally to mechanisms for locking doors in homes or buildings. More specifically, the present invention relates to an elastic door locking device which may be installed between a door knob and the wall adjacent the door, to absorb instantaneous impact of attempted forced entry.
2. Description of Related Art
In recent years, home intruders have become increasingly aggressive in their efforts to enter dwellings through locked doors. For example, recently intruders referred to as "kick burglars" have kicked or otherwise applied sufficient force on locking mechanisms to cause one or more of the locking components or door structure to fail. This trend of criminal activity in gaining access to the interior of a home or dwelling relies on the element of surprise, because the occupants are unable to react quickly enough to flee, contact police or other authorities, or take defensive measures.
In the past, primary and secondary locks have not been designed in a manner sufficient to absorb the impact of "kick burglars." First, the currently available primary and secondary locks are rigid, in that they are composed primarily of components which are unable to absorb the instantaneous forces imposed on the door and locking components. Additionally, because the current locking systems are fastened to the door and door frame by relatively short screws or other attachment means, they become dislodged if the door trim and/or door frame is shattered.
When an intruder kicks or otherwise applies instantaneous peak force to a door, current locking systems will fail in one of several ways. For example, the bolt on the typical dead bolt or keyless dead bolt will break through the door frame and door trim. Also, a secondary lock composed of a rigid metal or chain will reach the point where the maximum tensile strain on the metal and/or the frame is exceeded, and it will simply break. Additionally, screws which attach secondary locking devices to either the door itself or the door frame will be dislodged and ripped out of the door or its frame by the instantaneous force applied.
In the past, various door locking devices have been proposed which can be applied between the door knob and the adjacent wall to prevent the door from being opened from the outside. For example, U.S. Pat. No. 4,629,229 (Correnti, et al.) shows a flexible cable forming a loop on which a sleeve is positioned for engagement around a door knob. A loop of the cable is extended to slip over the sleeve and is then tightened to hold the door closed tightly. According to the '229 patent, the flexible cable is made of steel or the like, preferably covered by a plastic sheath. The cable is fastened to a wall stud with a screw or, in an alternative embodiment, with a fastener which grips the cable between upper and lower jaws which are attached to the wall stud. U.S. Pat. No. 4,288,119 (Geiger) shows a door locking cable which includes a flexible member which is looped around the door knob. The other end of the cable is secured to the door frame by a screw or bolt. According to the '119 patent, the cable is a multi strand steel cable which may be sheathed within a resilient material such as polyvinyl chloride. U.S. Pat. No. 5,466,022 (Derman) relates to a safety cable lock for knob operated door, which includes a plastic covered wire cable which loops around the door knob, and a screw or bolt in the frame stud to anchor the cable.
A number of devices also have been suggested to child-proof doors or cabinets, several of which involve an elastic component. U.S. Pat. No. 2,899,229 (Jenks) shows a child-proof cabinet lock which includes a coil spring extending between two adjacent door knobs. Similarly, U.S. Pat. No. 2,151,857 (Cassileth) shows a door handle lock extending between two adjacent door knobs. U.S. Pat. No. 3,012,806 (Ellis) shows a vehicle door safety cord which extends between the rear doors of automobiles. U.S. Pat. No. 4,281,865 (Nicholson) shows an interior door security lock with a horizontally extended wire which is slipped over the door knob. U.S. Pat. No. 4,715,629 (Robinson) relates to a child-proof closure device which includes a strap-like part which is non-elastic and a central elastic or spring loaded portion intermediate the strap. U.S. Pat. No. 5,387,018 (Pinkerton) relates to a child-proof refrigerator door latch which includes a shock cord mounted between two adhesive mounting plates.
The prior art fails to show an elastic door locking device capable of absorbing the instantaneous impact of "kick burglars" to prevent such intrusions.